Biomedical subjects

C Stenfors

Publications and source records attributed to C Stenfors.

47 records · Page 3Linked to original sources

PubMed1994

Effects of electro-acupuncture and physical exercise on regional concentrations of neuropeptides in rat brain.

The effects of single or repeated treatments with manual acupuncture (ACU), electro-acupuncture (ELACU) or physical exercise on neuropeptide Y (NPY), neurokinin A (NKA), substance P (SP), galanin (GAL) and vasoactive intestinal peptide (VIP)-like immunoreactivity (-LI) in different regions of the rat brain were studied. Initially the effect of microwave irradiation (MWI) was compared to decapitation on the recovery of neuropeptides, and significantly higher concentrations of SP-LI, NKA-LI and NPY-LI were found in the hippocampus, occipital cortex, pituitary and striatum following MWI. Repeated ELACU treatments significantly increased SP-LI, NKA-LI and NPY-LI in the hippocampus and NPY-LI in the occipital cortex. No changes were found in animals receiving ACU or performing physical exercise.

Acupuncture Therapy↗

PubMed1994

Repeated electroconvulsive stimuli: changes in neuropeptide Y, neurotensin and tachykinin concentrations in time.

1. The effects of repeated electroconvulsive stimuli (ECS) on neuropeptide Y (NPY)-, neurokinin A (NKA)-, substance P (SP)- and neurotensin (NT)- like immunoreactivity (-LI) levels in specific rat brain regions were studied in order to establish changes in peptide tissue concentrations in time after the last ECS. 2. The rats were sacrificed 15 minutes, 60 minutes, 1 day, 7 days or 15 days after the sixth sham ECS or ECS, using focused microwave irradiation. 3. Following dissection of the brains, peptides were extracted and measured in extract aliquots by radioimmunoassays. 4. ECS increased NPY-LI in both right and left hippocampus, frontal cortex and occipital cortex at 15 min, 60 min and 1 day after the treatments. Seven days following the last treatment, NPY-LI concentrations were elevated in the left hippocampus and occipital cortex but not in the corresponding right structures. Fifteen days following the last ECS treatment no changes in NPY concentrations were seen. 5. Also NKA-LI was increased in both the right and left hippocampus; the duration of changes was identical to those of NPY-LI. 6. No effects on SP- or NT-LI were found. 7. These results are in line with our hypothesis that one of the ECT's mechanisms of action might involve its effects on NPY and NKA.

Animals↗

PubMed1992

Electroconvulsive stimuli and brain peptides: effect of modification of seizure duration on neuropeptide Y, neurokinin A, substance P and neurotensin.

We studied the effects of modification of duration of seizures induced by electroconvulsive stimuli (ECS) on the changes in concentration of neuropeptide Y (NPY), neurokinin A (NKA), substance P (SP) and neurotensin (NT)-like immunoreactivity (-LI) in specific rat brain regions. Rats were divided into groups pretreated with saline, indomethacin, flurbiprofen or diazepam prior to either six sham ECSs or six ECSs. After sacrifice by focused microwave irradiation, brains were dissected into frontal cortex, occipital cortex, striatum, hippocampus, pituitary and hypothalamic sections. Peptides were extracted and measured in extract aliquots by specific radioimmunoassays. Repeated ECS increased NPY-LI and NKA-LI in the hippocampus and the occipital cortex. No effect on SP-LI or NT-LI was found. Indomethacin and flurbiprofen had no effect on the tonic seizure time following ECS, and they did not affect the ECS-induced alterations of the brain peptides. Diazepam pretreatment decreased the tonic seizure time following ECS in a dose-dependent manner. However, diazepam did not modify the ECS-induced increase in NPY-LI and NKA-LI concentrations. The results firmly establish that ECS leads to specific peptide increases in discrete rat brain regions and raise the possibility that such changes may not entirely be a consequence of seizures per se.

Animals↗

PubMed1992

Brain neuropeptides: changes by treatment with the convulsants pentylenetetrazole and bicuculline.

1. The effects of chemically induced convulsions, clinically similar to those elicited by electroconvulsive treatment (ECT), on brain regional distribution of neuropeptide Y-, neurokinin A-, substance P- and neurotensin-like immunoreactivities were studied in the rat. 2. Pentylenetetrazole (PTZ) and bicuculline (BIC) were used to induce grand mal seizures. Rats were divided into three groups receiving one of the following treatments: Saline, PTZ (45 mg/kg) or BIC (1.5 mg/kg). 3. After sacrifice by focused microwave irradiation, brains were dissected, peptides extracted and measured by specific radioimmunoassays. 4. Repeated grand mal convulsions induced by PTZ, in similarity to ECT, markedly increased NPY-LI concentrations in frontal cortex and hippocampus. In contrast to ECT, no changes in NKA- or SP-LI levels were seen. NT-LI was lowered in striatum. 5. Bicuculline effects were more circumscribed: some animals developed grand mal and died while convulsing (peptides not measured), others did not develop generalized seizures and were sacrificed after the fourth treatment. 6. The results demonstrate a similar effect of PTZ and ECT on regional NPY-LI concentrations and raise the possibility that grand mal, regardless of etiology, is necessary for effects on peptides.

Animals↗

PubMed1990

Effect of lithium on tachykinins, calcitonin gene-related peptide, and neuropeptide Y in rat brain.

The effects of lithium on brain regional concentrations of substance P (SP)-, neurokinin A (NKA)-, calcitonin gene-related peptide (CGRP)- and neuropeptide Y (NPY)-like immunoreactivities (-LI) were studied in rat. In the pilot study, rats were divided into three groups that were administered vehicle, or 1 or 4 mEq/kg lithium sulphate, respectively, intraperitoneally once/day for 9 days. In the second experiment, rats were divided into three groups receiving vehicle, or 1 or 2 mEq/kg lithium sulphate, respectively, intraperitoneally twice/day for 9 days. After sacrifice by focused microwave irradiation, brains were dissected, weighed, and frozen. Peptides were extracted and measured in extract aliquots by specific radioimmunoassays. Marked regional differences (P less than .001) were found for each of the peptides measured. In the pilot study the higher lithium dose, 4 mEq/kg, significantly raised neuropeptide levels. However, animals receiving this dose also showed signs of toxicity. In the second experiment, lithium increased SP-LI concentrations in striatum and hypothalamus (72 and 29%, P's less than .001 and .05). NKA-LI was also elevated in striatum (44%, P less than .01). CGRP-LI, in parallel to SP-LI, was increased in striatum and hypothalamus (58 and 78%, P's less than .05 and .01). In contrast, lithium decreased CGRP-LI in the pituitary gland (56%, P less than .01). NPY-LI was increased in striatum, and frontal and occipital cortex (30, 66, and 60%, respectively; P's less than .01, .01, and .05).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1990

Neuropeptides in brain: effects of microwave irradiation and decapitation.

Substance P (SP)-, neurokinin A (NKA)-, neurotensin (NT)-, neuropeptide Y (NPY)- and vasoactive intestinal polypeptide (VIP)-like immunoreactivity (Ll) were measured and characterized by specific radioimmunoassays (RIA) and reverse phase high performance liquid chromatography (HPLC) in extracts of rat brain. Concentrations of SP-Ll, NKA-Ll and NT-Ll in brains of decapitated animals were 59, 49 and 64 percent lower compared to those found in animals sacrificed by focused microwave irradiation (MW). In contrast, no difference in brain NPY-Ll and VIP-Ll levels was found between animals killed by MW and decapitation. HPLC chromatograms of SP-, NKA-, NT- and NPY-Ll showed the same immunoreactive components in extracts of brains from both groups of animals. Thus, no additional immunoreactive components were formed by MW compared to those found after decapitation. The present findings may reflect an MW-induced inhibition of peptidase activity or, perhaps, a more efficient extraction of certain neuropeptides following MW treatment. The results imply that the traditional methods of sacrifice may result in the measurement of spuriously low tissue concentrations of some peptides, e.g. tachykinins, in brain.

Animals↗

PubMed1990

Hypothalamic-pituitary-adrenal axis interaction with prostaglandins.

1. The major PGE2 plasma metabolite, 15-keto-13, 14-dihydro-PGE (PGEM) was measured during metyrapone, dexamethasone and ACTH tests in order to elucidate if plasma PGE was affected by short term changes of the hypothalamic-pituitary adrenal axis function in man. 2. Plasma PGEM, serum cortisol and serum 11-deoxycortisol were determined by RIA. 3. Metyrapone (an inhibitor of adrenal 11 beta-hydroxylase), 250-1000 mg was given orally at 4 hour intervals for 20 hours. PGEM, cortisol and 11-deoxycortisol were measured before and 10 and 22 hours after the start of metyrapone in 10 patients evaluated for pituitary disease. 4. Dexamethasone, 1 mg orally, was given at 23 hours on day one and 25 IU (1-24) ACTH were given iv at 8 hours on day two. Blood was drawn for determination of PGEM and cortisol at 8 hours day one, and 8 hours day two. After the ACTH injection, blood was drawn at 90 minutes (for PGEM) and at 120 minutes (for PGEM and cortisol). 10 subjects aged 21-62 years were studied. 5. Plasma PGEM levels were significantly increased after metyrapone, concomitantly with the lowering of serum cortisol levels. 6. No difference in the PGEM increase between patients with normal or subnormal 11-deoxycortisol response was found. 7. A significant increase in plasma PGEM levels was found when serum cortisol was suppressed 9 hours after dexamethasone administration. 8. Glucocorticoids inhibit synthesis of eicosanoids and the present results suggest that short term decrease in cortisol may stimulate PG synthesis.

17-Hydroxycorticosteroids↗

PubMed1990

Brain neuropeptides: tachykinins, neuropeptide Y, neurotensin and vasoactive intestinal polypeptide in the rat brain: modifications by ECT and indomethacin.

1. The effects of electroconvulsive treatment (ECT) and indomethacin on brain regional and right-left hemispheric distribution of tachykinins (TK), neuropeptide Y (NPY), neurotensin (NT) and vasoactive intestinal polypeptide (VIP) were studied in the rat. 2. Differences in peptide concentration between brain regions (frontal cortex, striatum, occipital cortex, hippocampus and hypothalamus) were found for all five peptides measured (all P values less than 0.001). 3. Furthermore, concentration differences between the hemispheres were found for SP, NKA and VIP (P less than 0.001, P less than 0.001 and and P less than 0.005, respectively), but not for NT and NPY. Peptide concentrations were generally higher in the right than the left hemisphere; e.g., SP levels in the frontal cortex, striatum, occipital cortex and hippocampus were 194, 390, 335 and 136 percent higher, respectively, in the right compared to the left hemisphere. The results are consistent with other findings of right-left brain asymmetries in distribution of some neurotransmitters. 4. One ECT had no detectable effects on concentrations of SP, NKA, NT or VIP. However, the mean concentration of NPY was higher in all regions (except the striatum) and both hemispheres (P = 0.004). 5. In the rats pretreated with indomethacin, levels of SP, NKA and NT were decreased (P less than 0.001, P less than 0.001 and P = 0.039 respectively), whereas the concentrations of VIP and NPY were not affected. For SP and NKA the decrease was apparent in all brain regions and both in the right and left hemispheres. For NT, the effect was more prominent in the left than in the right hemisphere.

Animals↗

PubMed1989

Effect of repeated electroconvulsive treatment on regional concentrations of tachykinins, neurotensin, vasoactive intestinal polypeptide, neuropeptide Y, and galanin in rat brain.

The effects of single and repeated electroconvulsive treatments (ECTs) on brain regional distribution of substance P (SP), neurokinin A (NKA), neurotensin (NT), neuropeptide Y (NPY), vasoactive intestinal polypeptide (VIP), and galanin (GAL) were studied in the rat. Rats were divided into four groups receiving one of the following treatments: one ECT, one sham ECT, six ECTs, or six sham ECTs. After sacrifice by focused microwave irradiation, brains were dissected into frontal cortex, striatum, occipital cortex, hippocampus, hypothalamus, and pituitary sections. Peptides were extracted by boiling the tissues in 1 mol/l acetic acid and measured in extract aliquots by specific radioimmunoassays. Marked regional differences (P = .0005) were found for each of the peptides measured. The highest concentrations of SP and NKA were found in the hypothalamus and, in descending order, in striatum, pituitary, frontal cortex, occipital cortex, and hippocampus. For NT, the highest level was found in the hypothalamus and, in descending order, in pituitary, striatum, hippocampus, frontal cortex, and occipital cortex. The highest VIP concentrations were measured in frontal and occipital cortex, followed by pituitary, hypothalamus, striatum, and hippocampus. The highest NPY and GAL concentrations were found in the hypothalamus and the pituitary; in frontal and occipital cortex, as well as in the striatum and hippocampus, the peptides levels were rather evenly distributed. Repeated handling (stress?) decreased both NT and GAL in frontal (P = .05 and .04) and occipital cortex (P = .09 and .07). ECT, one or six treatments, had no effect on SP, NKA, NT, VIP, or GAL concentrations in different brain regions. However, an increase in NPY concentrations in hippocampus (six sham ECTs vs.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1986

Bremazocine-induced backwards walking behavior in rats is mediated via opioid kappa receptors.

Bremazocine dose-dependently induced backwards walking behavior in rats after its SC injection. Only the (-) but not the (+) enantiomer induced backwards walking. Pretreatment with either naloxone or MR 2266 reduced the bremazocine-induced backwards walking. MR 2266 was at least ten times more potent than naloxone. These findings suggest that bremazocine-induced backwards walking is mediated via an agonistic action of the drug with opioid kappa receptors. The data may contribute to the discussion concerning opioid kappa receptors and the psychotomimetic effects of some opioid analgesic drugs.

Animals↗

PubMedDate not supplied

Microwave irradiation increases recovery of neuropeptides from brain tissues.

The effect of focused high energy microwave treatment (MW) on brain concentrations and molecular forms of substance P, neurokinin A, neuropeptide Y, neurotensin, galanin and calcitonin gene-related peptide was investigated. Groups of rats were treated as follows: 1) MW, storage for 60 min at 22 degrees C, 2) Decapitation, storage for 60 min at 22 degrees C. 3) Decapitation, storage for 60 min at 22 degrees C, MW treatment, 4) MW, decapitation, storage for 2 min at 22 degrees C and 5) Decapitation, storage for 2 min at 22 degrees C. Peptide concentrations were in all instances highest in the MW sacrificed groups. MW increased the concentration of intact peptides by rapid inhibition of peptidase activity and increase in peptide solubility/extractability.

Animals↗